Trends in Rates of Homicide -- United States, 1985-1994

During 1993, a total of 26,009 homicides were reported in the
United States; 71% were firearm-related, and one third of all
homicides occurred among persons aged 15-24 years (1). Since 1985,
national homicide rates have increased sharply, especially
firearm-related homicides and homicides among persons aged 15-24
years. However, based on data from the Supplementary Homicide
Report compiled by the Federal Bureau of Investigation and reports
from some cities, homicide rates have been stable or declining
since 1993. To examine this trend and to assess the relative
contributions of firearm- and nonfirearm-related homicide to these
recent changes, CDC analyzed national vital statistics data for
1985-1994. This report summarizes this analysis, which indicates
that overall rates of homicide increased from 1985 to 1991 and
decreased from 1992 to 1994, and that during these two periods,
rates for total firearm-related homicides and homicide among
persons aged 15-24 years increased then stabilized but remained at
record-high levels.

Data for 1985-1993 (the most recent year for which complete
data are available) were from final mortality statistics (FMS), and
data for 1994 were from the Current Mortality Sample (CMS). FMS are
based on information from death certificates submitted by all 50
states and the District of Columbia, and CMS data provide national
estimates based on a 10% systematic sample of death certificates
received monthly by the vital statistics offices in the 50 states,
the District of Columbia, and New York City. A homicide was defined
as death resulting from injury purposefully inflicted by another
person (including those caused by law enforcement officers or legal
intervention), for which the underlying cause listed on the death
certificate was International Classification of Diseases, Ninth
Revision (ICD-9), codes E960-E978. Population estimates are based
on data from the Bureau of the Census (2). Trends for both firearm-
and nonfirearm-related homicides for all ages and for persons aged
15-24 years were reviewed. To assess the accuracy with which the
CMS data reflect final statistics, 1993 CMS and FMS homicide rates
were compared. During sequential quarters of 1993, compared with
FMS quarterly homicide rates, CMS rates differed by -0.4%, -4.6%,
+1.2% and -4.6%, indicating the accuracy of weighted CMS rates for
estimating final homicide rates.

Quarterly homicide rates were analyzed using piecewise
regression models to account for the observed changes in linear
relations over time. Three time periods (1985-1987, 1988-1991, and
1992-1994) were selected for analysis based on a preliminary review
of scatter plots of observed rates and their apparent changes in
slopes. Statistical testing was conducted to determine whether the
slope of the predicted values of the regression line (i.e.,
predicted rates) changed over each of these time periods.
Statistical testing for a discontinuous piecewise regression model
also was conducted to determine whether the rate changed
significantly at the beginning of each new time period (i.e., "jump
point"). No significant jump points were observed, and analyses
consistently indicated that the slope of the regression line for
1985-1987 was similar to that for 1988-1991. Therefore, regression
lines are presented only for two periods: 1985-1991 and 1992-1994.
Overall results and interpretation of the piecewise model using two
pieces are no different from those using a model with three pieces.

During 1985-1991, the overall rate of homicide in the United
States increased significantly (p less than 0.01) (slope=less than
0.1, 4% annually); during 1992-1994, the rate decreased
significantly (p less than 0.01) (slope=-0.1, 1% annually)
(Figure_1). During 1985-1991, nonfirearm-related homicide rates
remained stable, and firearm-related homicide rates increased
significantly (p less than 0.01). During 1992-1994,
nonfirearm-related homicide rates declined significantly (p less
than 0.01), and firearm-related homicide rates stabilized.

During 1985-1991, the rate of total homicide increased
significantly for persons aged 15-24 years (p less than 0.01)
(slope=0.4, 16% annually). Firearm-related homicide rates for this
age group also increased during 1985-1991 (p less than 0.01)
(slope=0.4, 23% annually) (Figure_2), with most of the increase
occurring during 1988-1991. During 1992-1994, the rates of total
and firearm-related homicide were stable. For all other age groups,
the trend in firearm-related homicide rates followed a similar
pattern, with significant increases during 1985-1991 (p less than
0.01) and stable rates during 1992-1994 (Figure_2).
Nonfirearm-related homicide rates for persons aged 15-24 years and
all other ages were lower than firearm-related homicide rates and
were stable during 1985-1991 and decreased significantly during
1992-1994 (p less than 0.01).

Analysis of firearm-related homicide rates by sex for persons
aged 15-24 years indicates that rates for males and females
reflected the overall trend for this age group. Rates for females
were substantially lower than those for males. For both sexes,
rates increased significantly during 1985-1991 (p less than 0.01)
and stabilized during 1992-1994.

Reported by: Div of Violence Prevention, Office of Statistics and
Programming, National Center for Injury Prevention and Control; Div
of Vital Statistics, National Center for Health Statistics, CDC.

Editorial Note

Editorial Note: The findings in this report confirm that the
overall homicide rate increased rapidly during the late 1980s and
began to decline in 1992; in addition, nonfirearm-related homicide
rates decreased, and the percentage of firearm-related homicides
increased. During 1985-1994, the percentage of firearm-related
homicides among all homicides in the total population increased
from 60% to 72% and among persons aged 15-24 years, from 67% to 87%
(3). These increases illustrate that changes in overall homicide
rates primarily reflect changes in firearm-related homicides. The
stabilization of firearm-related homicide rates during
1992-1994 -- particularly among those aged 15-24 years -- reflects
a change from the increasing rates in previous years, even though
rates remain at record-high levels. The findings in this report
also
indicate the usefulness of CMS data as a source of information for
monitoring homicide in the United States. Because of the timely
availability of CMS data and their accuracy in reflecting final
mortality-based homicide rates, these data enable more timely
analyses
of temporal trends, objective policy formulation, and measurement
of progress toward public health goals.

The findings in this report are subject to at least two
limitations. First, because of the small numbers based on CMS data,
rates were not examined among age-, race-, and sex-specific
subgroups. Second, estimates for some causes of death may be
incomplete or skewed because reporting of the underlying cause of
death data may not have been complete when the monthly sample was
obtained (the data for this potential undercount are adjusted in
the annual summary {2}).

Strategies for preventing homicide and violence require
integration of approaches from multiple disciplines, including
criminal justice, education, social services, community advocacy,
and public health. For example, public health approaches to prevent
violence have focused on 1) changing individual knowledge, skills,
and/or attitudes; 2) changing the social and physical environments;
and 3) increasing community awareness of the causes and prevention
of violence. The public health community also has recognized the
influence of social class and poverty on violence. Communities
increasingly are adopting programs emphasizing strategies to
enhance the skills of youth and parents to reduce violence. These
strategies include, for example, 1) school-based curricula that
teach coping, communication, and mediation skills (4); 2)
family-intervention programs that focus on parental training to
positively alter parental practices and family cohesion (5); and 3)
preschool efforts to develop intellectual and social skills (6).
Because evaluation of prevention strategies is a critical component
of public health interventions, CDC is evaluating the effectiveness
of selected programs in reducing violent behavior and injury (7).

Homicide and assaultive violence now are recognized as global
public health problems. Although the U.S. homicide rate ranks
higher overall and higher for males aged 15-24 years than those of
other highly industrialized countries (8,9), in many less-
industrialized countries homicide rates exceed those in the United
States (8). To address this global problem, in May 1996 the 190
nations of the World Health Organization (WHO) passed a resolution
declaring violence a worldwide public health problem, urging member
states to assess the public health impact of violence, and
requesting the Director-General of WHO to initiate a science-based
public health approach to violence prevention. This resolution
provides a scientific framework for action throughout the world
addressing global violence.

Tolan P, Guerra N. What works in reducing adolescent violence:
an empirical review of the field. Boulder, Colorado: University
of
Colorado, Boulder, Institute for Behavioral Sciences, Center for
the Study and Prevention of Violence, 1994:29.

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